High-permittivity Ceramic Substrate Research Articles

A microstrip coupler through a narrow slot in the common ground plane of a two-sided microstrip circuit board

An empirical design of a microstrip coupler through a narrow slot in the common ground plane of a two-sided microstrip circuit board is presented. The power transmission between a microstripline on a high-permittivity ceramic substrate (εr = 9.8) and one on a low-permittivity Teflon-based substrate (εr = 2.2) is measured at near-millimeter-wave frequencies for a varying slot length. It is demonstrated that such a contactless transition can successfully be used with an acceptable loss in order to couple the power from one side to the other of a two-sided microstrip circuit board.

Capacitors compatible with thick film circuit technology

The paper describes three approaches to the problem of manufacture of capacitors by methods compatible with thick film technology. In the first, the capacitor is regarded entirely as a discrete component and is manufactured or purchased independently. The problems of integration become those of surface bonding and of the protection of devices with irregular outlines.The second approach is to produce the resistor network on a high permittivity ceramic substrate, and manufacture capacitors in situ by the printing of appropriate electrode regions. This technique has the advantage of simple processing and produces co-planar components, but it necessitates a compromise on thermal and mechanical properties of the substrate material.The third and probably the best approach is to produce the capacitor by printing and firing of a suitable dielectric glaze. This introduces no compromise on substrate, no design allowances for strays, the component is co-planar and is produced by identical processes to the resistors. Multi-layer techniques offer the prospect of significantly wider range of values, and adjustable capacitors may eventually permit close tolerances to be achieved. This approach involves complexity of the process sequence for active R-C networks, possibly with multi-layer capacitors.